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The Lost OP Wiki: Revo - Sensor Calibration
Revo - Sensor Calibration Proper sensor calibration is essential for precise and reliable operation of the controller. The sections below explain the procedures for calibrating each of the sensors; of these, the Thermal Calibration is typically done once with the controller itself, while the other calibrations are done more frequently with the board mounted on the aircraft . In the video below, Corvus Corax demonstrates the calibration procedures. Thermal Calibration This calibration is not necessary, but will improve the performance of the controller. With the completion of this procedure, the Revo will be able to accurately compensate for changes in temperature within the calibrated temperature range, typically ambient air temperature +/- 15 degrees Celsius. Artificial cooling and heating is used to achieve the desired target range. If the operating environment's temperature range exceeds the calibrated range, the procedure should be repeated to ensure sensor accuracy. Before starting, verify that the OPLink modem is disabled to avoid damaging it. The OpLink modem must never transmit without an antenna. How to verify OPLink is disabled Steps: # Connect a USB cable to the controller and then the board in a plastic bag. Seal the bag but leave one end of the USB cable outside the bag so that it can be connected to the computer later. This will protect the board from condensation. # Prepare a means of warming the Revo rapidly to the target high temperature in still air. Movement of the controller or airflow around the controller will affect the results and must be avoided. A lamp in a shoe box is the method we will assume here. # Place the bagged Revo/cable assembly in the freezer for approximately 20 minutes. # Remove the bagged Revo from the freezer, connect the USB cable to the computer, insert the Revo in the warming mechanism and start the calibration in GCS. # When the recorded temperature reaches the target range, unplug the lamp and wait for the calibration to finish. # Press Save when you are satisfied with the results, or repeat the steps as necessary. How to check the stored calibration range You can check the temperature once it is saved by inspecting the min-max values on the System page under Settings/AccelGyroSettings/temp_calibrated_extent. Below is screen shot of uncalibrated board showing 0 for both min & max. Tip Icon Upon completion of the Thermal Calibration procedure, export UAV settings so that you can later import UAV settings without having to remove the controller from the vehicle in order to redo this procedure; for example, after erasing settings. If you do so, uncheck all settings except Revo Settings each time. Accelerometer Calibration With the completion of this procedure, the Revo will be able to accurately compensate for changes in orientation of the controller in flight. The controller must remain perfectly still during each step; any vibration or movement will cause the calibration to fail. To initiate the accelerometer calibration, press the Start button. Follow the onscreen instructions, orienting the controller as shown and pressing Save Position each time when the board is perfectly still. Repeat the calibration if it fails, taking more care to ensure the board doesn't move. Once the procedure is successfully completed, press Save. View the detailed steps # On the Calibration Tab, Click start "Accelerometer calibration" 2. Place the board as shown in the picture on screen and click "Save Position" 3. Place the board as shown in the picture on screen and click "Save Position" 4. Place the board as shown in the picture on screen and click "Save Position" 5. Place the board as shown in the picture on screen and click "Save Position" 6. Place the board as shown in the picture on screen and click "Save Position" 7. Place the board as shown in the picture on screen and click "Save Position" 8. Place the board as shown in the picture on screen and click "Save Position" 9. Once calibration finished it will Show "Calibration Successful" 10. If the Calibration Failed, you will need to restart the Accelerometer Calibration over. Once calibration is finished successfully, click "Save" Magnetometer Calibration With the completion of the magnetometer calibration procedure, the Revo will be able to accurately compensate for regional magnetic fields. Proper magnetometer calibration is essential for all GPS flight modes. Ensure that the Home Location has been set prior to commencing calibration as the calibration process needs to take into account the local magnetic fields at your location. Please refer to the Revo - Setting Home Location page. Small movements during this calibration will not affect the results. Only relative orientations matter; it is not necessary to use magnetic North as North. Before you begin this calibration, ensure that the aircraft is in its final flight configuration. Wires with power running through them must be tightly twisted or braided to eliminate electromagnetic fields; they should also be routed to keep them as far away from the Revo as possible. Hold your aircraft in the air while performing this calibration and ensure that the controller is well away from metal objects or sources of magnetism. You should ensure that the magnetic conditions on the model match those of the flight configuration and that you have considered magnetism when building your aircraft. The vehicle should be fully powered with propellers removed for this calibration. To initiate the magnetometer calibration, press the Start button. Follow the onscreen instructions, orienting the controller as shown and pressing Save Position each time when the board is pointed in the right general direction. Repeat the calibration if it fails. Once the procedure is successfully completed, press Save. If the aircraft's electrical configuration varies in any way after the calibration, the magnetometer will need to be re-calibrated. View the detailed steps # On the Calibration Tab, Click start "Magnetometer calibration" # Place the board as shown in the picture on screen and click "Save Position" # Place the board as shown in the picture on screen and click "Save Position" # Place the board as shown in the picture on screen and click "Save Position" # Place the board as shown in the picture on screen and click "Save Position" # Place the board as shown in the picture on screen and click "Save Position" # Place the board as shown in the picture on screen and click "Save Position" # Place the board as shown in the picture on screen and click "Save Position" # Once calibration finished it will Show "Calibration Successful" # If the Calibration Failed, you will see above, you will need to restart the Magnetometer Calibration over. Once calibration is finished successfully, click "Save" Board Level Calibration With the completion of this procedure, the Revo will be able to accurately compensate for uneven mounting. The controller must remain perfectly still during each step as any vibration or movement will cause the calibration to fail. To initiate the Board Level Calibration, place the aircraft on a flat, level surface and press the Start button. Follow the onscreen instructions, orienting the aircraft as shown and pressing Save Position each time when it is perfectly still. Repeat the calibration if it fails, taking more care to ensure the aircraft doesn't move. Once the procedure is successfully completed, press Save. View the detailed steps # On the Calibration Tab, Click start "Board Level calibration" # Place the board as shown in the picture on screen and click "Save Position" # Place the board as shown in the picture on screen and click "Save Position" # Once calibration finished it will Show "Calibration Successful" Once calibration is finished successfully, click "Save" Gyro Bias Calibration With the completion of this procedure, the Revo will be able to more accurately use the gyros. The controller must remain perfectly still during each step as any vibration or movement will cause the calibration to fail. To initiate the Board Level Calibration, place the aircraft on a flat, level surface and press the Start button. Once the calibration is completed, it will show the "Calibration Successful" message. Repeat the calibration if it fails, taking more care to ensure the aircraft doesn't move. Once the procedure is successfully completed, press Save. View the detailed steps # On the Calibration Tab, Click start "Gyro Bias calibration" # Once calibration finished it will Show "Calibration Successful" Once calibration is finished successfully, click "Save" Hints and Tips Saving Thermal Calibration Data Once your're done, it is advantageous to save the thermal calibration data for the board. This will prevent one from having to redo it at a later stage as usually the Revolution is installed into a vehicle by then and removing it is a pain. Also, if one erased all the board settings this data will be lost, and unless you have saved it, you will have no choice but to remove the Revolution from the vehicle and repeat the process. The thermal calibration data is associated with the barometric pressure sensor, as well as the Gyros and Accelerometers. # With the board plugged into the GCS, use the "File" menu option and select "Export UAV Settings...". Choose a suitable name for the file and click Save. # Now open the UAV file in a text editor, and remove all UAVObjects except "AccelGyroSettings" and "RevoSettings". You file should look something similar to the example below. Note all version information has been removed too. You should only have the UAVOjects shown. # Save the file. # If you have more than one Revolution, it is a good idea to give the file a descriptive name to allow one to associate it with a specific Revolution. Loading data from another board could have unpredictable results. Importing Thermal Data # To import the thermal data saved in a UAV file, use the "File" menu option and select "Import UAV Settings...". # Select the appropriate file, and then click Save to Board Flash. After importing thermal data from a saved UAV file, it is very important to note that you MUST redo the following calibrations: * Accelerometer * Magnetometer * Board Level * Gyro Bias This is because conditions on the vehicle would most probably have changed, at it is safest to repeat the other calibration steps. Except Thermal of course. If you see a status message "Warning (ObjectID mismatch)" as in the example below, then the associated UAVObjects have been changed in a release subsequent to the date on which you saved the original calibration data. In this case - DO NOT import the file. This is when you have no choice but to repeat the thermal calibration. Vibrations Make sure you sort out and minimise all vibrations in your vehicle. If you have a vibration problem, you are going to struggle with everything.